Give any four factors necessary for a healthy person.

Four factors necessary for a healthy person are-

1. The surrounding environment of the person should be clean so that the air and water-borne diseases do not spread.
2. There should be the maintenance of a certain level of personal hygiene to prevent infectious diseases.
3. Sufficient nourishment and food are necessary for the immune system to work efficiently.
4. Immunization or prior vaccination against severe diseases should be completed on time.